1. Field of the Invention
This invention relates to replacing an existing load center with a renovation load center without the need for rewiring the distribution system.
2. Background Information
Load centers house the connections between the incoming lines of an electric power distribution system and the numerous branch circuits in an installation, such as a residence or light commercial or industrial facility. Overcurrent protection is provided for the branch circuits in older load centers by fuses but now in most installations by circuit breakers. Additional protection, such as surge protection, is provided in some load centers. Typically, the load center will have a main circuit breaker as well as separate breakers for each of the branch circuits.
The load center includes an enclosure that may be fabricated from sheet metal or molded of an insulative resin. Housed in the enclosure is a branch circuit assembly, also commonly referred to as the interior, which typically includes a pair of line buses secured by a support insulator to the rear wall of the enclosure. The fuses or circuit breakers connect each branch hot conductor to one of the line buses, or to both buses in the case of a two pole breaker. The branch circuit assembly also includes one or more neutral terminal blocks to which the branch circuit neutral conductors are secured. In some cases, such as for ground fault circuit breakers, a ground terminal block or blocks are also provided in the enclosure.
There comes a time when the existing load center needs to be replaced, such as where a fuse load center is replaced by a load center with circuit breakers, or for instance, where branch circuits are added or updated. Typically, in existing load centers, the incoming lines are made as short as possible. It is common for them to be too short to reach the required terminals in the replacement load center. However, the gauge of the incoming lines is large enough that it is difficult, time consuming and expensive to splice extensions onto the incoming lines.
There is a need, therefore, for an improved load center and method of upgrading a load center which does not require the splicing of the incoming lines.
These needs and others are satisfied by the invention which is directed to a renovation load center for a distribution system having incoming lines and a plurality of branch conductors, each including a hot conductor and a neutral conductor. The renovation load center includes an enclosure having a rear wall and a branch circuit assembly mounted in the enclosure on the rear wall with line terminals at the one end of the assembly. An incoming terminal block is provided adjacent the one end of the branch circuit assembly and has line terminations for the incoming lines. Cables engaging the line terminations connect the incoming lines to separate ones of the line terminals on the branch circuit assembly. The incoming terminal block can be mounted on the rear wall of the enclosure adjacent the line terminals on the branch circuit assembly. The branch circuit assembly can include a circuit breaker mounting assembly with the line terminals at the one end and at least one neutral/ground terminal block. An additional neutral/ground terminal block can be provided adjacent the incoming terminal block.
The enclosure of the load center may include a main enclosure in which the branch circuit assembly is mounted and an auxiliary enclosure in which the incoming terminal block is mounted. In this case, the cables extend from the incoming terminal block in the auxiliary enclosure to the branch circuit assembly in the main enclosure.
The invention also embraces the method of upgrading an existing load center by disconnecting the input lines and branch circuit conductors from the existing load center, removing the existing load center, mounting a renovation load center in place of the existing load center, providing a renovation terminal block in an enclosure of the renovation load center, connecting the incoming lines to terminations on the renovation terminal block, connecting cables from the terminals on the renovation terminal block to line terminals on the branch circuit assembly of the renovation load center, and connecting the branch circuit hot conductors and neutral conductors in the renovation load center. The renovation load center may have a single main enclosure, in which the renovation terminal block is mounted, or alternatively the renovation panel may have a main enclosure housing the branch circuit assembly and an auxiliary enclosure housing the renovation terminal block mounted adjacent to the main enclosure. In the latter case, connecting the cables includes routing the cables from the auxiliary enclosure to the main enclosure.